Gas burner

ABSTRACT

A gas burner for a shaft kiln having a hollow body, into the lower portion of which a noninflammable gas can be supplied for flowing upwardly therethrough, a tubular member extending coaxially within this hollow body, into which a fuel gas can be supplied for flowing also upwardly therethrough, the tubular member having an outlet head portion received thereabout adjacent to the upper end thereof; a plurality of cone-shaped deflectors are received about the body and the tubular member, these deflectors tapering upwardly and being vertically spaced from one another, whereby at least two chambers are formed therebetween for the noninflammable gas and fuel gas to issue into these chambers, respectively, from the body and from the tubular member.

United States Patent [54] GAS BURNER 2 Claims, 1 Drawing Fig.

521 u.s.c| 239/418,

431/177,43l/160,239/423 s1 lnLCl ..F23dl5/02 so FieldofSearch 431/160,

[56] References Cited UNlTED STATES PATENTS 1,583,362 5/1926 Ostendorf... 431/350 3,182,712 5/1965 Fink etal. 1. 431/177 3511587 5/1970 Jansen et al 431/160 Primary Examiner Edward G, Favors Att0rneyWaters. Roditi, Schwartz & Nissen ABSTRACT: A gas burner for a shaft kiln having a hollow body, into the lower portion of which a noninflammable gas can be supplied for flowing upwardly therethrough, a tubular member extending coaxially within this hollow body, into which a fuel gas can be supplied fior flowing also upwardly therethrough, the tubular member having an outlet head portion received thereabout adjacent to the upper end thereof; a plurality of cone-shaped deflectors are received about the body and the tubular member, these deflectors tapering upwardly and being vertically spaced from one another, whereby at least two chambers are formed therebetween for the noninflammable gas and fuel gas to issue into these chambers, respectively, from the body and from the tubular member.

GAS BURNER The present invention relates to apparatus for supplying gases into shaft kiln, such as shaft for burning materials and, more particularly, it relates to gas burners for such kilns; the teachingsof the present invention are applicable in kilns for burning various materials, eg in metallurgy, in sugar-making industry, in the industry of construction materials, etc.

Known in the art are gas burners comprising a pyramidshaped structure into the upper portion of which a fuel gas and a nonfuel, or noninflammable gas are supplied through the respective separate conduits, these gases issuing in two perpendicular directions through the slots provided for the purpose in the body of the kiln, the gases being directed under a deflecting member to be mixed, and after the mixing the gases flow into the cooling zone of the shaft kiln through a space between the deflecting member and the body of the burner.

As a nonfuel gas may be employed recirculation gas, nitrogen or any other inert gas, as well as any mixture of these gases.

However, these known burners have considerable disadvantages.

First, the radius of the action of such a burner is limited on account of the gases issuing therefrom but in two directions, whereby it is impossible to install burners of this kind in kilns of large diameters;

Second, the protective pyramid-shaped deflector of the burner presents an additional resistance to the flow of the gas, and thus reduces the speed of this flow, which affects propagation of the gas into the bulk of the layer of the material being burned, and this affects the uniformity of the distribution of the mixture comprising the fuel gas, the nonfuel gas and air over the cross-sectional area of the kiln, which, in its turn, results in a nonuniform thermal stress over the cross section of the kiln and hence-to nonuniform burning of the material.

Besides, the presence of the common gas mixing chamber, or space might lead, in case the pressure of the fuel gas supply rises above a specified level or else in case the pressure of the nonfuel gas drops below another specified level, to the mixture of the gases finding its way into the nonfuel gas conduit and to considerable variations taking place in the proportion of the gases in the mixture, whereby a portion of the fuel gas might not burn altogether.

Furthermore, should the oxygen content in the nonfuel gas mixture be increased, the actual ratio of the volume of the nonfuel gas being supplied to that of the fuel gas, as calculated for a zero air content, is reduce, whereby the inflammation point of the fuel gasnonfucl gas-air mixture is brought down, and the normal speed of flame propagation is increased. This results in the gas mixture being inflamed in a close vicinity of the burner, i.e. in the cooling zone of the shaft kiln whereby the material burning zone is lowered, which means that the burning duty is affected, and in certain cases might lead to a burner breakdown.

With gas burners constructed in accordance with the present invention it becomes possible to achieve sufficiently uniform distribution of a fuel gas mixture in shaft kilns of practically any size.

The objects of the present invention are accomplished in a gas burner for a shaft kiln, comprising a vertically extending hollow body into the lower portion of which a noninflammable gas can be supplied for flowing upwardly through said body, a tubular member extending within said hollow body coaxially therewith; into which a fuel gas can be supplied for flowing also upwardly through said tubular member, in which gas burner, according to the present invention, said tubular member carries an outlet head portion adjacent to the upper end portion thereof, from which said fuel gas is adapted to issue from said tubular member, said body and said tubular member being associated with a plurality of cone-shaped deflector members received thereabout, said cone-shaped deflector members tapering upwardly and being vertically spaced from one another, whereby at least two chambers are formed therebetween, one of said at least two chambers com municating with the interior of said hollow body for said noninflammable gas to issue from said body into said one chamber, the other one of said at least two chambers communicating with the interior of said tubular member for said fuel gas to issue from said tubular member into said other chamber.

According to a preferred embodiment of the present invention, it is advisable for said outlet head portion to comprise a flange member received about said tubular member and having a plurality of nozzle-shaped openings made thcrethrough.

Referring now in particular to the appended drawing, the gas burner, embodying the invention, includes a tubular body 1, which is the main structural part of the burner, rigidly at tached to a mounting structure 2 which is meant for securing the burner in a kiln. The tubular body 1 serves as a conduit for the nonfuel gas of the gas mixture. This structural feature of the herein disclosed burner makes it possible to manufacture the tubular body 1 from common grades of steel, since the nonfuel gas supplied into the body 1 serves simultaneously as an adequately efficient cooling medium for the burner structure, whereby, even with the walls of the tubular body 1 being comparatively thin, the body is able to withstand a considera' ble pressure of a great load of material burned in the furnace.

A tubular member extends within the body 1 and coaxially therewith, the member 3 serving as a supply conduit for the fuel gas of the gas mixture. The tubular member 3 being received within the body 1, it is sufficiently protected from any mechanical damage, whereby any highly undesirable leakage of the gas is sufficiently prevented. The upper extremity of the fuel gas conduit 3 projects somewhat above the upper end portion of the body 1 with its upper end flange 4, the conduit 3 having in the projecting portion thereof a plurality of openings 5 made therethrough, uniformly spaced about the circumference of the conduit. Disposed downwardly of the openings Sis an outlet head portion 6 including a flange with a plurality of nozzle-shaped ports 7 spaced circumferentially thereabout. The entire projecting structure is covered from above by a cone-shaped cap 8 protecting the openings 5 in the fuel-gas supply conduit 3 and the nozzle ports 7 from being clogged by the material being burned in the furnace. The upper portion of the cone-shaped cap 8 forms, together with the flange 4, a closed fuel gas supply chamber.

Disposed downwardly of the fuel gas supply chamber 9 is a pair of cone-shaped deflectors 10, received about the tubular body 1 and spaced axially therealong. The deflectors are meant to protect a plurality of nonfuel gas outlets 11 made through the wall of the tubular body 1 intermediate of the deflectors, the deflectors defining therebetween a nonfuel gas chamber 12.

The nonfuel outlets 11 are uniformly spaced about the perimeter of the tubular body 1, for distributing the nonfuel gas uniformly in all directions radially of the body, the outlets lill being each of a comparatively great flow passage area, since the volume of the nonfuel gas supplied into the shaft of the kiln is considerably greater than the amount of the fuel gas supplied thereinto.

in order to increase the rigidity of the herein disclosed burner structure, the latter is provided with a plurality of axially extending fins 13, l4, 15 which project radially from the periphery of the tubular body 1, these rigidity fins interfering in no degree with the propagation of the streams of the gases.

The lowermost one of the two cone-shaped deflectors 10 has a closure plate 16 secured to the lower extremity thereof and to the periphery of the tubular body 1, the closure plate preventing the material being burned from getting into the space defined by the internal surface of the deflector and the adjacent portion of the periphery of the body 1.

The convenience in assembling the burner structure in the kiln, the burner is provided with an eyebolt l7 in the upper portion thereof.

.The herein disclosed gas burner can be manufactured from the most common grades of rolled stock and structural materials; it doesnt require precise machining of its constituent parts; the parts can be assembled by simple welding techniques, and, therefore, the burner can be manufactured completely in practically any mechanical shop. Assembling of the herein disclosed burner is also quite simple and does not require any reconstruction of the existing kilns.

The burner operates in the following manner.

The fuel gas is supplied from an external source under suffi cient pressure into the fuel gas conduit 3 and issues therefrom through the openings 5 in the upper portion of the conduit into the closed chamber 9 formed under the cone-shaped cap 8. The chamber 8 having for the bottom thereof the outlet head portion including the flange with the nozzle-shaped ports 7, the gas issues therefrom through these nozzle ports 8 in streams having a sufficient speed for uniform distribution of the fuel gas over the entire cross-sectional area of the shaft of the kiln in the cooling zone thereof.

The nonfuel, or furnace gas is supplied into the tubular body 1, wherefrom it issues through the outlets ll into the space defined intermediate of the two cone-shaped deflectors l0,

' i.e. into the nonfuel gas chamber 12 formed between the,

deflectors. From the chamber 12 the nonfuel gas finds its way into the cooling zone of the shaft kiln. While passing upwardly through the tubular body 1, the nonfuel gas effects cooling of the latter, whereby it doesn't require additional cooling ar rangements for normal performance of the burner.

After having been supplied into the cooling zone of the kiln, the gases difiuse into the layer of the material being burned, the gases propagating themselves into spaces and cavities left between the lumps of the material, substantially uniformly over the entire cross-sectional area of the shaft kiln. Simultaneously, the flows of the two gases are turbulized, which provides for their intensive mixing with each other, whereby there is formed a mixture containing the fuel gas, the nonfuel gas and air which gets into the kiln through the bottom discharging openings orthrough other means. This mixture is characterized by its inflammation point being considerably higher than that of a simple fuel gas-air mixture, this inflammation point being proportional to the content of the nonfuel gas in the mixture, whereby it becomes possible to set positively the conditions under which the gas mixture would inflame precisely in the burning zone of the kiln, by adjusting the content of the nonfuel gas in the gas mixture. Such adjustment might be called for, e.g. when the composition of the material or the proportion of its different fractions vary, as well as in other cases which might influence the location of the burning zone in the kiln.

Among the advantages featured by the herein disclosed gas burner are its high efficiency and the simplicity of the structure. The high capacity of the burner, which is high against the overall size thereof, means that incorporation of burners of the kind, embodying the present invention, brings about saving of metal, as compared with burners which are widely used at present in shaft kilns. The simplicity of the structure of the burner, as well as the fact that there is neither precise machining nor any complicated treatment involved in the production of its constituent parts, makes it possible, as it has been already stated, to manufacture the burner in practically any mechanical workshop, by means of all-purpose machines, from materials which are always available. Consequently, the manufacturing cost of burners of the herein disclosed kind is low. The burner, furthermore, can do without a water cooling system in its operation, since the body thereof is sufficiently cooled by the nonfuel gases passing therethrough.

The high capacity of the burners of the herein disclosed kind provides for improved operation of shaft kilns incorporating them, thanks to a kiln being able to operate with a reduced amount of burners, as compared with the hitherto known burners; moreover, with the amount of the burners in the kiln thus reduced, the burners present less obstruction to the progress of the material being burned through the burning uniformity of the time during which the material is burned in the burning zone, which results in more uniform heating of the material and in an increased capacity ofthe furnace...

Whcn constructed in accordance with the present invention, the burner proper is not loaded with adjustment and measurement means which are positioned at external supply lines which fact not only simplifies the design of the burner, but also facilitates the control and maintenance of the entire system.

It is also possible to position temperature pickups inside a burner, embodying the invention, in any area thereof since the coaxial arrangement of the gas conduits provides for the pickups thus installed not affecting any noticeably the flow of the gases therethrough. When such pickups are installed, automation can be introduced into the operation of the burners, e.g. for maintaining automatically the conditions under which the gas mixture is inflamed precisely within the burner zone, by adjusting correspondingly the proportion of the gases in the mixture, e.g. when the proportion of the different fractions in the material being burned varies.

When burners of the herein disclosed kind are incorporated in a shaft kiln, distribution of the gas mixture over the crosssectional area of the burning zone becomes more uniform, on account of turbulization and diffusion of the fuel gas-airinert gas mixture, as the latter propagates itself through the layer of the material in the cooling zone. Uniform supply of the fuel gas across the kiln provides for uniform thermal stress of the material within the burning zone and thus inhibits fusing together of lumps of material, whereas with the existing burners insufflciently uniform distribution of the fuel gas results in local overheating and in such fusing together.

With the burner of the herein disclosed kind being disposed within the cooling zone of the kiln, the temperature conditions of its operation are improved, as compared with those of the existing burners, whereby the operational life of the burner becomes comparatively longer.

Furthermore, with the burner being installed in the lower portion of the cooling zone, the assembling of the burner, as well as its maintenance become more simple. The burners may be mounted and secured either on baffle plates, etc., already existing in the kiln, or else on support beams specially provided for the purpose in the lower portion of the cooling zone.

With the amount of burners per one kiln being reduced, thanks to the incorporation of burners embodying the present invention, the total amount of measuring and control instruments and apparatus associated with the kiln can also be reduced.

With the amount of burners and the amount of measuring and control apparatus and instruments having been reduced, less service personnel is required.

We claim: I

l. A gas burner for a shaft kiln comprising: a substantially vertically extending hollow body having means in the lower 7 portion thereof through which a noninflammable gas can be supplied for flowing upwardly through said body; a tubular member extending within said body and coaxially therewith, said tubular member also having means through which a fuel gas can be supplied thereinto for flowing upwardly therethrough; said hollow body and said tubular member having means adjacent to their respective upper end portions, through which said noninflammable gas and said fuel gas, respectively, can issue therefrom, said tubular member carrying an outlet head portion received thereabout adjacent to said upper portion thereof; a plurality of cone-shaped deflector members received about said hollow body and said tubular member adjacent to said respective upper portions thereof,

. another chamber.

said fuel gas to issue from said tubular member int0 said 2. A gas burner, as set forth in claim 1, wherein said outlet head portion comprises a flange received about said tubular member and having a plurality of nozzle-shaped openings made therethrough. 

1. A gas burner for a shaft kiln comprising: a substantially vertically extending hollow body having means in the lower portion thereof through which a noninflammable gas can be supplied for flowing upwardly through said body; a tubular member extending within said body and coaxially therewith, said tubular member also having means through which a fuel gas can be supplied thereinto for flowing upwardly therethrough; said hollow body and said tubular member having means adjacent to their respective upper end portions, through which said noninflammable gas and said fuel gas, respectively, can issue therefrom, said tubular member carrying an outlet head portion received thereabout adjacent to said upper portion thereof; a plurality of coneshaped deflector members received about said hollow body and said tubular member adjacent to said respective upper portions thereof, said plurality of cone-shaped deflector members being vertically spaced and tapering upwardly, so that at least two chambers are formed therebetween, one of said at least two chambers communicating with the interior of said hollow body for said noninflammable gas to issue from said hollow body into said one chamber, another one of said at least two chambers communicating with the interior of said tubular member for said fuel gas to issue from said tubular member into said another chamber.
 2. A gas burner, as set forth in claim 1, wherein said outlet head portion comprises a flange received about said tubular member and having a plurality of nozzle-shaped openings made therethrough. 